Problem

Calendar share invitation emails are sent to external domains as a blank email with no content and no link to share a calendar.

Solution

Set the email to send as Rich Text

For Microsoft Outlook 2010:

To send messages in TNEF, follow these steps:

1. Click the File tab, click Options, and then click Mail.
2. In the Compose in this message format list, click Rich Text, and then click OK.

For Microsoft Office Outlook 2007:

Follow these steps to send messages in TNEF:

1. On the Tools menu, click Options, and then click the Mail Format tab.
2. In the Compose in this message format list, click Rich Text, and then click OK.

For Microsoft Office Outlook 2003 and earlier versions of Outlook:

Follow these steps to send in TNEF:

1. On the Tools menu, click Options, and then click the Mail Format tab.
2. In the Send in this message format list, click to select Microsoft Outlook Rich Text Format, and then click OK.